A Detailed Investigation of Staged Normal Injection into a Mach 2 Flow

A study of the staged injection of two jets of air behind a rearward facing step into a Mach 2 flow was performed using the SPARK 3-D Navier-Stokes code. Calculated mole fraction distributions were compared with an extensive set of planar mole fraction measurements made with a laser induced iodine fluorescence technique. A statistical measure, the standard deviation, was used to help assess agreement between calculation and experiment. Overall, good agreement was found between calculated and measured values. Generally, agreement was better in the far field of the injectors. The effect of grid resolution was investigated by calculating solutions on grids of 60,000, 200,000, and 450,000 points. Differences in the solutions on the two finer grids were small. However, the mole fraction distributions were distinguishable. The effect of turbulence modeling was investigated by employing three different algebraic models for the jet turbulence: the Baldwin-Lomax model, the Prandtl mixing length model, and the Eggers mixing length model. Overall, the Eggers mixing length model was found to be superior for this case. Finally, the effect of the jet exit conditions was examined. A recently proposed Mach number distribution at the jet exit was found to slightly improve agreement between measurement and calculation

What are the priorities for improving cataract surgical outcomes in Africa? Results of a Delphi exercise.

PURPOSE: The quality of cataract surgery delivered in sub-Saharan Africa (SSA) is a significant constraint to achieving the elimination of avoidable blindness. No published reports from routine SSA cataract services attain the WHO benchmarks for visual outcomes; poor outcomes (<6/60) often comprise 20% in published case series. This Delphi exercise aimed to identify and prioritise potential interventions for improving the quality of cataract surgery in SSA to guide research and eye health programme development. METHODS: An initial email open-question survey created a ranked list of priorities for improving quality of surgical services. A second-round face-to-face discussion facilitated at a Vision 2020 Research Mentorship Workshop in Tanzania created a refined list for repeated ranking. RESULTS: Seventeen factors were agreed that might form target interventions to promote quality of cataract services. Improved training of surgeons was the top-ranked item, followed by utilisation of biometry, surgical equipment availability, effective monitoring of outcomes of cataract surgery by the surgeon, and well-trained support staff for the cataract pathway (including nurses seeing post-operative cases). CONCLUSION: Improving the quality of cataract surgery in SSA is a clinical, programmatic and public health priority. In the absence of other evidence, the collective expert opinion of those involved in ophthalmic services regarding the ranking of factors to promote quality improvement, refined through this Delphi exercise, provides us with candidate intervention areas to be evaluated

Solvent selectivity by an organoclay complex

The selective adsorption from a series of binary solutions on an organoclay complex has been studied in relation to the gelling ability of this organoclay. Adsorption isotherms were obtained for a series of polar organic solvents in toluene. The isotherms were of the usual "S" or "U" type depending upon the polar component. The crossing point in which the concentration of the binary solution did not change due to selective adsorption was assumed to be the concentration of the adsorbed phase. The ability for the polar component to adsorb was interpreted in terms of three properties of that polar component: size, dielectric constant and its association with the hydrocarbon. It was found that a relationship can be determined between the concentration of the polar component in the adsorbed phase and the gel strength. A model was proposed for the structure of the gel based on the adsorption of the polar component

The Prevalence of Pulmonary and Upper Respiratory Tract Symptoms and Spirometric Test Findings Among Newspaper Pressroom Workers Exposed to Solvents

To investigate the relationship between exposure to organic solvents and the presence of pulmonary and upper respiratory tract mucous membrane symptoms, we conducted a cross-sectional study of 215 newspaper pressroom workers who were occupationally exposed to organic solvent and lubricant mixtures. Thirty-four compositors, who were not occupationally exposed to the solvents or lubricants, served as controls. Pressroom workers and compositors underwent spirometric testing and were also asked about the presence of cough, phlegm, hemoptysis, dyspnea, wheezing, chest tightness, nose or throat irritation, eye irritation, and sinus trouble. The spirometric results did not significantly differ between the two groups. However, the pressroom workers were significantly more likely to report pulmonary or upper respiratory tract mucous membrane symptoms than were compositors (P \u3c 0.005). An exposure-response relationship could be demonstrated when comparing the number of solvents exposed with the total number of symptoms (P \u3c 0.001). Similarly, an exposure-response relationship could be demonstrated when comparing the frequency of use of each of the seven solvents with the total number of symptoms (P \u3c 0.002). Each of these findings was supported in a multivariable linear regression model that adjusted for potential confounders such as age, smoking history, and number of years in the industry. A high prevalence of these symptoms was reported even though the degree of exposure to solvents and lubricants was within the current permissible exposure limits

Checklist of the Vascular Flora of Lyon and Sioux Counties, Iowa

The combined vascular flora of Lyon and Sioux counties, Iowa, based upon field and herbarium study, is composed of 612 species, of which 454 species (74%) occur in both counties. The Lyon County vascular flora consists of 561 species, including 13 state endangered, 9 state threatened species, and 102 non-native species. The Sioux County vascular flora consists of 506 species, including 2 state threatened species and 106 non-native species. The floras are most notable for the presence of plants with floristic affinities to the Great Plains to the west of Iowa. They also have a very high percentage (18%-20%) of their floras comprised of non-native species, reflecting the intensity of human activities on the landscape

Bill Viola ou l’image sans représentation

Bill Viola affirme que l’ère de la vision optique est terminée et, malgré cela, ses œuvres donnent l’impression d’une parfaite évidence visuelle : ce paradoxe d’une image non destinée à la vue est le thème de cet article. La première thèse développée grâce à la comparaison de la production du vidéaste avec l’art figuratif et le théâtre est qu’elle a une autonomie esthétique spécifique qui se fonde sur l’élision préalable du seuil de la fiction. La deuxième thèse est que B. Viola propose à nouveau la conception de cet œil innocent dont on pensait qu’il n’existait pas, sous la forme d’un corps sincère dont l’existence reste encore à prouver. Il crée en effet des configurations audiovisuelles qui permettent, par la mise en avant de l’expressivité originaire de l’homme, de produire un effet persuasif, affirmatif même, sur le spectateur qu’il soit naïf ou sophistiqué tout en sollicitant son système nerveux. La troisième thèse est que dans toute sa production est à l’œuvre le même problème esthétique, à savoir le délitement de l’identité psychologique du spectateur qui fait l’expérience sur lui-même du véritable thème des vidéos : l’émotion. Ces images vont alors s’incorporer dans l’homme.Bill Viola claims that the era of optical vision is over and, despite this, his works give the impression of a perfect visual evidence. This article sets out to look at the paradox of an image which is not aimed to the sight. First, in comparing the work of this video-maker with figurative art and theatre, we can see that it partakes of a specific aesthetic autonomy grounded in the previous elision of the threshold of vision. Second, we can see that B. Viola offers once more the innocent eye which was believed not to exist, under the form of a sincere body whose existence remains to be proven. He indeed creates audio-visual configurations which allow by bringing forward the original expressivity of man, to produce a persuasive or even claiming effect on the viewer, be he naive or sophisticated in using his nervous system. Thirdly, the same aesthetic problem operates in his whole work: the deleting of psychological identity of the viewer experiencing within himself the theme of the video, this theme being emotion. Such images will then be incorporated within him

A Typology of Factors Influencing Seniors' Participation in Strength Training in Gyms and Fitness Centers

Older people are less likely to engage in strength training than their younger counterparts, despite the substantial benefits of this form of exercise for preventing and addressing age-related physical decline. In many countries, strength training programs are available for older people yet are undersubscribed. The aim of this study was to identify the factors influencing older people's participation in strength training at gyms and fitness centers to provide insights into potentially effective recruitment and retention strategies for this population. A total of 79 individuals from four stakeholder groups (seniors, fitness center instructors and managers, health practitioners, and those involved in policy) were interviewed to identify and explicate relevant factors. A detailed typology was developed that provides insights into potential strategies at five ecological system levels: intrapersonal, interpersonal, organizational, social, and policy. The typology can be used as a tool for identifying opportunities to encourage strength training participation among older people